knightmb said:
Is there any additional energy saving when cooling the gear oil is mixed in?
Cooling the gears would make the oil stay thicker (more viscosity), and thicker oil loses even more energy. I say don't cool the oil too much since you actually want it to get as thin as possible, within limits.
knightmb said:
....the fans kick on. All of that uses energy, not sure how much, haven't measured.
Fans are wasting energy. Those fans are getting rid of the heat during charging. It's not much lost energy. Certainly losses though. Gone.
On that same note, I was once curious as to how much heat losses you get charging & discharging an Li-Ion battery. I think I found you only lose around 2% lost to waste heat, depending on the amps going in or out, but usually not much.
knightmb said:
..... avalanche effect within another system of the Leaf (cooling system) that uses a lot more power....
That's true to some extent. Think about it from the viewpoint of how much power (watts) has to flow on the wires feeding the motor. If the gearbox is more efficient, less watts are needed on those wires, less waste heat is generated. A small amount less. Same goes for better lower resistance tires, it results in the need for less watts on those wires & less heat too.
In fact, maybe the best way to look at all this is to use some hard facts we have. The Road Load, which has been measured on Leafs many times. Road Load includes the gearbox internal frictional drag, and all the dissipative energy losses up into the motor's internal windage losses.
Therefore, Road Load is great to tell us how many Watts must flow out of the battery itself !!!
Road Load at 60 MPH is 489 Newtons.
So that is 26.8 meters/second x 489 N = 13.1 kW power being drawn out of the battery at 60 mph.
Road Load from a 2013 Leaf (similar in a 2020 Leaf) from https://inldigitallibrary.inl.gov/sites/sti/sti/5737951.pdf page 5.
Routing 13.1 kW power through the gearbox, 1% of that would be 0.131 kW savings using low visc oil. Like burning a 100 watt light bulb waste at 60 mph.